252 



black. PERMAFROST 



[Ch. 14 



Diagrammatic cross section through Alaska, along long. 150% showing approximate 

 distribution of permafrost and thickness of active layer 



Diagrammatic cross section through Asia, along long. 120°, showing approximate distribution of 

 permafrost and thickness of active layer. (Modified from unpublished cross section by I.V. Poire'.) 



■I Active layer Y '^\ Discontinuous permafrost 



tttttti Continuous permafrost fcs^J Sporadic permafrost 

 Fig. 2. Representative cross sections of permafrost areas in Alaska and Asia. 



-10 -5 



Degrees Centigrade 

 5-5 5-5 



100 



200 



300 



400 



500 



(a) 



N 



Nome, 

 I Alaska. 

 > After 



Taber 

 (1943a) 



Bukachacha, U.S.S.R. 



After 



D.V. Redozubov, 1946; 



Courtesy I.V. Poire' 



(b) 



(c) 



Fig. 3. (a) Representative temperature profiles in areas of continuous perma- 

 frost, (b) Representative temperature profiles in areas of discontinuous perma- 

 frost, (c) Hypothetical temperature profiles in areas of sporadic permafrost. 



